G4PDefSplitter.hh

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// $Id: $
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// 
// ------------------------------------------------------------
//
//      GEANT 4 class header file 
//
// ---------------- G4PDefSplitter ----------------
//
// Utility template class for splitting RW data for thread-safety from
// classes: G4ParticleDefinition, G4VDecayChannel.
//
// ------------------------------------------------------------
// History:
// 01.25.2009 Xin Dong: First implementation from automatic MT conversion.
// ------------------------------------------------------------
#ifndef G4PDEFSPLITTER_HH
#define G4PDEFSPLITTER_HH

#include <stdlib.h>

#include "globals.hh"
#include "pwdefs.hh"
#include "G4AutoLock.hh"

template <class T>  // T is the private data from the object to be split
class G4PDefSplitter
{
  public:

    G4PDefSplitter() : totalobj(0) {
        G4MUTEXINIT(mutex);
    }

    G4int CreateSubInstance()
      // Invoked by the master or work thread to create a new subinstance
      // whenever a new split class instance is created. For each worker
      // thread, ions are created dynamically.
    {
      G4AutoLock l(&mutex);
      totalobj++;
      if (totalobj > slavetotalspace)  {
          l.unlock();
          NewSubInstances();
          l.lock();
      }
      return (totalobj - 1);
    }

    void NewSubInstances()
      // Invoked by each worker thread to grow the subinstance array and
      // initialize each new subinstance using a particular method defined
      // by the subclass.
    {
      G4AutoLock l(&mutex);
      if (slavetotalspace  >= totalobj)  { return; }
      G4int originaltotalspace = slavetotalspace;
      slavetotalspace = totalobj + 512;
      offset = (T *) realloc(offset, slavetotalspace * sizeof(T));

      if (offset == 0)
      {
        G4Exception("G4PDefSplitter::NewSubInstances()",
                    "OutOfMemory", FatalException, "Cannot malloc space!");
      }

      for (G4int i = originaltotalspace; i < slavetotalspace; i++)
      {
        offset[i].initialize();
      }
    }

    void FreeSlave()
      // Invoked by all threads to free the subinstance array.
    {
      if (!offset)  { return; }
      free(offset);
      offset = 0;
    }

    
    T*   GetOffset() { return offset; }
    
    void UseWorkArea( T* newOffset ) // ,  G4int numObjects, G4int numSpace)
    {
        // Use recycled work area - which was created previously
        if( offset && offset!=newOffset )
        {
            if( newOffset != offset )
            {
                G4Exception("G4PDefSplitter::UseWorkspace()",
                            "TwoWorkspaces", FatalException,
                            "Thread already has workspace - cannot use another.");
            }
            else
            {
                G4Exception("G4PDefSplitter::UseWorkspace()",
                            "TwoWorkspaces", JustWarning,
                            "Thread already has a workspace - trying to set the same again.");
            }
        }
        offset= newOffset;
        // totalobj= numObjects;
        // totalspace= numSpace;
    }
    
    T* FreeWorkArea() // G4int* numObjects, G4int* numSpace)
    {
        // Detach this thread from this Location
        // The object which calls this method is responsible for it.
        //
        T* offsetRet= offset;
        
        offset= 0;
        
        return offsetRet;
    }
    
  public:

    G4PART_DLL G4ThreadLocalStatic G4int slavetotalspace;
    G4PART_DLL G4ThreadLocalStatic T* offset;

  private:

    G4int totalobj;
    G4Mutex mutex;
};

#endif